Nut



SR Search Roon OR 2,386,197

/ Vf f Oct. 9, 1945. H. G. nAwsoN NUT Filed July 8. 1944 3 nventor 2#Ecran 6.1M ws 0N MLZ., 575655:.

(lttomeg @als Uil Patented Oct. 9, 1945 NUT Hector G. Dawson, Glendale,Long Island, N. Y., assignor to Aircraft Screw Products Company, Inc.,Long Island City, N. Y., a corporation of New York Application July 8,1944, Serial No. 5445042 10 Claims.

The invention relates to a composite nut comprising a barrel with aninner cylindrical surface and a coll therein between a bottom iiange anda to'p rim of the barrel, both inwardly projecting, andscrew-thread-forming portions of the coil convolutions projectinginwardly of the ilange and rim. In general, the barrel of a nut of thementioned type has to withstand relatively high stresses, particularlyin the bottom flange and top rim, as it is desired to reduce thedimensions of such composite nut as much as admissible so that it doesnot materially, or only as little as possible. exceed the conventionalonepiece nut in size as to both its height and its diameter orcircumference. It is also desired that the external shape of the nutdoes not materially diil'er from the usual form. Furthermore, a torqueapplied to the barrel must be transmitted to the coil so that the nutcan be screwed on and on a correspondingly threaded screw bolt, and formany uses it is even required that a certain limited movement of thecoil relatively to the barrel is possible, notwithstanding the mentionedtransmission of the torque from the one to the other. This latterrequirement must be taken into consideration especially when theresilient quality of the coil is utilized as in various types of stop orloci: nuts.

The present invention aims to provide a composite nut which is bettersuited to fulil the mentioned requirements than the composite nuts ofconventional structure. It consists essentially in that the nutcomprises, in addition to the barrel and coil, an anchoring membersecured interiorly of the barrel near its top end and embodying a faceor faces for engagement by the coil so as to limit or to preventmovement of the latter, be it in axial or peripheral direction inrelation to the barrel.

Further objects and details of the invention will be apparent from thedescription given hereinafter and the accompanying drawing illustratingseveral embodiments thereof by v ay of example. In the drawing,

Fig. 1 is a longitudinal cross-section of a nut according to theinvention;

Fig. 2 is a top plan view thereof;

Fig. 3 is a top plan view of the anchoring member thereof;

F18. 4 is a cross-section of another embodiment;

Figs. 5 and 6 are top and bottom plan views respectively of theanchoring member thereof;

Fig. 7 is a side elevation of the coil and anchoring member in thebarrel of a third embodiment, the barrel being in section;

Fig. 8 is a perspective view of the anchoring member thereof;

Fig. 9 is a cross-section of the barrel prior to the insertion of thecoll and the anchoring member;

Fig. 10 is a cross-section of a modification of Fig. 7:

Fig. 11 is another modification thereof; and

Figs. 12 and 13 are top plan views of the coil and anchor ring of Fig.11.

With reference to the drawing, Figs. 1 to 3, the nut according to theinvention comprises a barrel l with cylindrical inner surface 2, abottom flange 3 and an inwardly turned top rim 4 which in its originalposition has the form 5 indicated in dotted lines. A cylindrical coil 6,preferably of resilient material, ts into the barrel and bears on thetop surface 'l of the flange 3. The crosssection of the coilconvolutions may be of any suitable configuration withscrew-thread-forming portions 8 inwardly projecting with respect to theopenings 9 and III of the bottom flange and the top rim respectively. Itis necessary to secure the coil to the barrel so that a torque can betransmitted from the one to the other. However, it is desirable to allowfor a slight relative movement of the two parts in either an axial or a,peripheral direction or both. This is particularly true if theresiliency of the coil is used in order to obtain a locking action ofthe nut. It will be clear that the resiliency of the total length of thecoil cannot be put to play if points of the coil intermediate its endsare iixed to the barrel. Even a rigid xation of both coil ends willpermit only certain deformations so that, e. g. if one convolution isslightly expanded, one or several others musi; be contracted. or if thespacing of two adjacent convolutions is increased the spacing of othersmust be accordingly decreased. In consequence, if a rigid connection isapplied such connection should be provided on one end only. However, inthat event it is not immaterial which end is to be selected for thispurpose. If a coil of the kind here under consideration is screwed on athreaded bolt, there is the tendency of the convolutions to expand. Suchexpansion is desirable, particularly in that convolution which isleading i. e. the bottom convolution, when the composite nut is appliedto such bolt in order to facilitate the inter-engagement oi' the twomembers. Obviously. the deformation of the leading convolution is leastrestricted if the anchoring point is far remote therefrom. For thisreason, it is the trailing or top end of the coil which according to theinvention is anchored to the nut barrel, whereas the leading or bottomend should be free to move or deform within limits. It will beunderstood that such limits will be extremely narrow. A hundredth oreven a thousandth of an inch of freedom to move or to deform may be allthat is required according to the tolerances used in making the nut andthe bolt for which the nut is destined. However, in other cases, it maybe preferable to provide for a larger freedom to an extent say of oneortwo-tenths of an inch. Although it is possible to secure the topconvolution of the coil directly to the barrel, I prefer to provide ananchoring member for the connection of coil and barrel for reasons to beexplained hereinafter.

In the illustrated embodimentl the bottom and top surfaces and I2respectively of the coil are plane at right angles to the nut axis, andthe bottom surface bears on the ange 3. In the top surface I2 one or aplurality of radial grooves I3 are provided for the purpose of anchoringthe coil. The anchoring member consists of a ring I4 with projections I5on its lower face and a plurality of grooves or notches I6 in its topface.V

The ring fits into the barrel and its inner diameter substantiallycorresponds to that of the opening I of the top rim 4. When the ring |4is placed on top of the coil the projections I t into the grooves I3while material of the top rim 4 engages the grooves or notches I5 of thering when the rim of the barrel is tilted over by swag ing or any othersuitable operation from its original position 5 into the final positionand shape 4. Thus it will be clear that the anchor ring is held againstmovement relatively to the barrel rim and the upper coil end isprevented from turning relatively to the barrel by its engagement withthe anchor ring. Still, beginning from its lower end, the coil mayexpand as much or as little as e. g. a sliding fit of the coil in thebarrel permits is a screw bolt exerts radial pressure on theconvolutions. It has been stated hereinbefore that it may becomenecessary to transmit considerable forces between the members of thecomposite nut. There will be among other stresses e. g. an appreciablepressure per unit area on the top face 1 of the flange 3, and the toprim 4 with its material engaging the grooves I6 of the anchor ring willhave to resist a torque or at least a, major portion of a torque set upbetween coil and barrel. This calls for a high grade or hard material ofthe barrel. On the other hand, the barrel material should besufficiently ductile to permit the tilting over of the top rim 4 fromits original position 5. The s expedient of hardening the nut barrel ingeneral after the nut is otherwise finished is not applicable becausethe material of the coil may be harmfully aiected. The following method,however, which is also part of the invention, gives satisfactoryresults. The barrel is made of a ductile material which can be hardened,in the shape shown in Fig. l and with its top rim erected in the formindicated at 5. Then, the lower portion of the barrel with its flange 3and up to e. g. one-third of its height is subjected to a hardeningtreatment so that the hardness gradually decreases upwardly from thelevel of the flange top surface 1. This leaves the top portion of thebarrel soft. Thereupon, the coil 6 and the anchor ring I4 are insertedand the top rim swaged or otherwise turned inwardly down upon the anchorring so that material of the rim enters the grooves or notches I6 of thering. When the nut is in its finished shape the top rim is subjected toa hardening treatment wherein care is taken that the effect of suchtreatment does not extend downward beyond the lower level of the ring.In this manner, hardening of the barrel in its portions where requiredcan be accomplished without interfering with the structure of the coilmaterial, because the thickness of the ring I4 can be used as a safetyzone in which the effects of the treatment can decrease to a minimum.Although other methods of hardening may be useful in connection with thementioned treatment, the socalled and well-known induction hardeningmethod appears to be particularly well suited for the purpose here underconsideration with respect to both the lower portion of the barrel andits top rim.

In the modification illustrated in Figs. 4 to 6, the barrel I is of thesame kind and shape as that of Fig. l. The coil 20, however, has across-section suitable for a round thread rather than for a V-thread asin the case of the coil 6. This difference is not material from theviewpoint of the present invention as stated hereinbefore. However, thetop end of the coil ends in a face 2| which is substantially parallel tothe coil axis. In other words, the top face 22 of the coil is helicallycurved according to the pitch of the coil. This top face bears againstan anchor ring 23 the bottom face 24 of which is correspondingly curvedso as to furnish a bearing surface for at least the major portion of thetop coil convolution. Between the highest and lowest portion of thissurface there is a substantially radial face 25 adapted as an abutmentfor the coil end face 2|. The ring is secured to the barrel by suitablemeans which are shown as being of the same kind as in Fig. 1, that meansthe top face 25 of the ring is provided with grooves I6 into whichmaterial of the barrel rim engages after the latter has been turned downupon the assembled coil and ring. It will be noticed that a smallclearance is shown between the end face 2| of the coil and the abutmentface 25 of the anchor ring. Such clearance allows for a greaterdeformation and movement of the coil in the barrel than otherwisepossible, and its actual size may be selected according to theparticular condition for which the nut is destined. If this nut isscrewed on a bolt the torque applied to the barrel will cause a slightshift until the face 25 of-the ring bears against the end face 2| so asto transmit the torque to the coil. Thereby a very small gap may occurbetween the lower plane face 26 and the top face 1 of the barrel flangeso that the coil is free to stretch a little and to fit as closely aspossible the bolt threading when progressively more convolutions comeinto engagement. When finally the nut bears upon a supporting face,further tightening of the nut will cause a tension whereby the coil ispressed against the top surface 1 of the flange 3 so that the total loadof the nut is transmitted through the bottom flange 3. If the nut is tobe screwed o the bolt, a relative shift of coil and barrel may occur inthe opposite direction. In that event the top face of the coil willslide along the helical face 24 of the ring. Thereby, the pressurebetween th bottom flange of the barrel and the coil will be increaseduntil the friction between the two overcomes the friction in thethreading whereupon the entire nut will follow the torque applied to thebarrel.

In certain instances it may be a disturbing factor that the swaging ofthe barrel rim 4 tends to compress the coil and anchor ring with theresult that resilient deformations of the coil are i Lil, 1151,)

rendered impossible, unless great care is taken in the production toavoid such happening. This would be particularly harmful where the nutis to be used as a lock nut and where for that purpose the coil isformed for instance with waves, in either axial or radial direction. Themodification shown in Figs. '1 to 9 illustrates a structure whereby suchundesirable compressions of the coil can be avoided.

The arrangement in Fig. '1 is very similar to that of Fig. 4, the coil30 differing from the coil 2U merely by the waving indicated at 3|. Theanchor ring 32 has a helical lower face 33 of the same pitch as the coil30, but is not waved in the manner of the coil convolutions. In order tosecure the ring to the barrel 34 against turning, the top portion 4| ofthe barrel is provided while still in its erected position as shown inFig. 9, with axial grooves 35 forming shoulders 36 at a prede. terminedlevel. Into the grooves 35 engage radially extending projections 31 ofthe anchor ring 32. The projections 31 engaging the shoulders 36 cannotbe pressed downward when the top rim of the barrel is turned over tobear upon the top face 36 of the anchor ring as shown in Fig. '1. Itwill be clear that in this manner it is possible to provide for anydesired freedom of coil deformations, notwithstanding pressure exertedon the ring 32 in an axial direction. Itis, of course, also possible toprovide, in addition to the projections 31, grooves in the top face ofthe anchor ring such as the grooves |6 in Figs. l and 2, to be engagedby the material of the top rim of the barrel. In other respects, the nutof Fig. 7 is similar to the structure shown in Fig. 4 so that thetransmission of a torque applied to the barrel will be accomplished bythe ring face 39 abutting against an end face 40 of the top coilconvolution.

Fig. 10 illustrates a modification of the embodiment shown in Fig. 7. Itdiffers from the latter essentially in that the coil 50 has not only ahelical top surface, but also a helical lower end with a, face in asubstantially radial plane parallel to the nut axis. Correspondingly,the bottom flange 52 of the barrel 53 has a helical top surface 54 tosupport the coil, and a surface 55 to serve as an abutment for the coilsurface 5|. Similarly, the anchor ring 56 has a lower helical surface ofthe type shown in the embodiments of Figs. 4 and 7 with an abutment face51 for engagement with the upper end face 56 of the coil. 'I'he upperportion of the ring 56 differs from ring 32 in that it is provided witha serrated conical periphery 59 so as to engage a conical shoulder 59 ofthe barrel, the serrations cutting into the barrel material when thering is pressed down into position. It will be clear that such structureserves the same purpose as lthe projections 31 of the ring 32, insecuring the ring to the barrel against axial as well as peripheralrelative movement. In other respects, the nut of Fig. is similar to thenut 0f Fig. '1. Hence, when the nut is applied to a bolt, coil 50 willbear with its face 58 against the face 51 of the ring 56 in the samemanner as the face 40 will abut against face 35 in Fig. '1. When,however, the nut of Fig. 10 is screwed off the bolt, the coil will tendto turn in the barrel so that the face 58 moves away from face 51 andthe lower coil end face 5| will abut against face 53 to prevent furtherturning of the coil 50 relatively to the barrel 53, whereas in the caseof Fig. '1 such further relative movement is prevented when the coil hasinitially turned suiiiciently to clamp Ithe coil firmly between theplane top surface of the bottom ange and the anchor ring owing to thehelical shape of the bottom surface of the latter. It will be understoodthat the initial relative movement will be caused in both instances bythe friction between the coil convolutions and the bolt threading.Furthermore, in both instances contraction of the coil owing to suchfriction will be prevented on account of the fact that the forceresisting relative movement of the coil acts against the lower coil end.iAny locking action of such nut will, therefore, relay more or lessexclusively on such locking features as e. g. the waving 3| of the coilconvolutions.

However, it is possible also to provide the nut with self-lockingqualities without such additional measures like the mentioned waving.This is shown in Fig. 11. The barrel in this case may be provided witheither a fiat top surface 60 of the bottom flange as illustrated or witha helical ange surface of the type of Fig, 10. 'I'he lower portion ofthe coil may be shaped accordingly but it is necessary that there isoriginally sumcient clearance between the lower end face of the coil andthe top face of the flange to allow for a limited axial expansion of thecoil. Such clearance is indicated at 62 between the face 63 of the coil64 and the face 60 of the barrel flange. Contrary thereto, the top endof the coil must be so anchored as to prevent it from any turningmovement relatively to the barrel, and owing to the requirement of acertain axial deformation or even movement of the coil, it is to bepreferred that no axial force is exerted on the coil when the barrel rimis swaged as hereinbefore described. In other words, the anchor ring 65should be held in a suitable manner as e. g. according to Fig. '7 or 10.Thus, ring 65 is provided with radial projections 66 which bear onshoulders 36 of the barrel 34. Rotation of the ring in the barrel may beprevented by such means as hereinbefore described, or by indenta tions61 of the top face to be engaged by the material of the barrel rim, orby other suitable means. The top end of the coil 64 may be secured tothe anchor ring in the manner shown in Fig. l. However, in view of thepossibility of an axial 'movement a greater axial length of the engagingfaces is to be preferred. For this reason the end 68 of the coil is soshaped as to project upwards. The thread forming portion 59 of the topconvolution does not extend into the upturned end 68 so that a bolt isfree to be screwed through the whole length of the nut. The anchor ring65 is substantially shaped like ring 32 of Fig. 8, except for a recess69 to receive therein the coil end 68. It will be noticed that therecess is provided between the widest and the narrowest portion of thering 65.

Now it will be clear that if the nut of Fig. 11 is screwed on a bolt,the convolutions of the coil will tend to expand until the nut comesinto contact with a supporting surface whereupon the coil will be firmlypressed on the top surface 60 of the bar el flange. If, however, a,torque is applied to the nut in a direction to screw it ofl a bolt, thefriction between bolt threading and the coil will tend to contract theconvolutions which to a certain degree can follow such tendency owing tothe freedom of the lower coil end. In consequence, the coil may increaseits grip on the bolt with a desired locking action.

It will be understood that the abovementioned hardening process may beadvantageously used in the production of the last described nut as wellas of any one of the preceding nuts.

Having now described several embodiments of my invention, it will beapparent to those skilled in the art that many alterations andmodifications thereof may be made without departing from the spirit andessence of my invention, which shall be limited only by the scope of theappended claims.

Iclaim:

1. A composite nut. comprising a barrel with cylindrical inner surfaceand an interiorly projecting bottom flange, a. wi\re cggjittingjntmsaidbarrel and. having a botto-rfi face substantially corresponding to theshape of the top face of said flange, the convolutions of said coilincluding screw-thread-forming portions, and an anchoring member securedto said barrel on top of said coil and including faces for engagementwith the top portion of said coil to transmit torques in both directionsof turning from the barrel to the coil with freedom of the lower coilend to deform slightly and accordingly to shift relatively to the barrelflange.

2. A composite nut comprising a, barrel with cylindrical inner surface,a bottom flange and a top rim both interiorly projecting, a wire coilfitting into said barrel and having a bottom face substantiallycorresponding to the shape of the top face of said flange, theconvolutions of said coil including screw-thread-forming portions, andan anchor ring between said coil and said rim and secured to said barrelagainst relative movement, said ring including faces for engagement withthe top portion of said coil to transmit torques in both directions ofturning from the barrel to the coil with freedom of the lower coil endto deform slightly and accordingly to shift relatively to the barrelflange.

3. A composite nut comprising a barrel with cylindrical inner surface, abottom ange and a top rim both interiorly projecting, a wire coilfitting into said barrel and having a bottom face substantiallycorresponding to the shape of the top face of said flange, theconvolutions of said coil including screw-thread-forming portions, ananchor ring between said coil and said rim and secured to said barrelagainst relative rotation, means in connection with said ring and saidbarrel to prevent said ring from shifting in an axial direction, saidring including faces for engagement with the top portion of said coil totransmit torques in both directions of turning from said barrel to saidcoil.

4. A nut as claimed in claim 3, the top face of said coil and the bottomface of said ring being substantially plane and including interengagingindentations and projections.

5. A nut as claimed in claim 3, said coil and said ring having helicallycurved top and bottom faces respectively and including abutment faces inplanes substantially parallel to the nut axis.

6. A nut as claimed in claim 3, said coil and said ring having helicallycurved top and bottom faces respectively, said ring being provided witha recess, and the upper coil end including an upwardly extendingprojection in engagement with said recess.

7. A composite nut comprising a barrel with cylindrical inner surface, abottom ange and a top rim both interiorly projecting, a wire coilfitting into said barrel and having a bottom face substantiallycorresponding to the shape of the top face of said ange, theconvolutions of said coil including screw-thread-forming portions, ananchor ring between said coil and said rim and secured to said barrelagainst relative rotation. means in connection with said ring and saidbarrel to prevent said ring from shifting in an axial direction, saidring including faces for engagement with the top portion of said coi1 totransmit torques in both directions oi turning from said barrel to saidcoil, and the length of the coil, when the nut is not in use, beingslightly smaller than the space available for the coil between said ringand said flange.

8. A composite nut comprising a barrel with a cylindrical inner surface,a bottom flange and a top rim, both inwardly projecting, a. wire coilfitting into said barrel and an anchor ring between said coil and saidrim and secured to said barrel, the bottom face of said rim, the topface of said ange and the top and bottom faces of said coil beinghelically curved with the same pitch, said ring and said flangeincluding abutment faces for the coil ends in planes substantiallyparallel to the nut axis, and said coil being slightly shorter than thedistance between said abutment faces.

9. A composite nut comprising a barrel with a cylindrical inner surface,a bottom flange and a top rim, both interiorly projecting, a wire coilfitting into said barrel on top of said flange, the convolutions of saidcoil including screw-threadforming portions, and an anchor ring betweensaid coil and said rim and secured to said barrel against relativemovement, said ring and the top portion of said coil including means totransmit torques from the one to the other, said barrel including alower portion hardened prior to the insertion of said coil and saidring, and including an upper portion hardened after the forming of theinwardly projecting rim.

l0. A composite nut as claimed in claim 9 wherein said hardened lowerbarrel portion extends from the bottom face of the barrel upwards beyondthe level of said flange, and said upper hardened portion extends fromthe top surface of the barrel slightly below the lower level of saidrim.

HECTOR G. DAWSON.

